Nervous system

• The nervous system is a communication system between the body's internal cells and organs and the external world
• Sensory information from the PNS travels up the spinal cord to the brain
• Motor messages from the brain travel down the spinal cord to the PNS
• The CNS consists of the brain and the spinal cord
• Role of CNS: processes information received from the body's internal and external environments AND activates appropriate responses
• The brain is comprised of an organised network of neurons, where certain areas and structures have specialised functions
• Roles of the brain:

  • Receive and process, sensory information received from the environment
  • Initiates, responds and controls all bodily actions and functions
• The spine cord is an intricate and delicate cable of nerve fibres stretching from the base of the brain to the lower back
• Roles of the spinal cord

  • Carries sensory information from the peripheral nervous system to the brain
  • Carries motor information from the brain to the peripheral nervous system
• The peripheral nervous system is the entire network of nerves located outside the CNS
• Role of the PNS:

  • Carries sensory information from the rest of the body to the CNS
  • Transmits motor information from the CNS to the rest of the body
• The PNS has 2 subdivisions called the somatic nervous system and the autonomic nervous system
• Somatic nervous system: Carries sensory (afferent) information to the CNS and motor (efferent) information from the CNS
• Autonomic nervous system: Self-regulating system that controls involuntary functions of internal muscles, organs and glands - necessary for survival
• The autonomic nervous system has two divisions called the sympathetic nervous system and the parasympathetic nervous system
• The sympathetic nervous system arouses the body when we experience an extreme emotion or feel threatened
• The parasympathetic nervous system calms or restores the body to the normal state of functioning after an extreme emotion emotion subsides or a threat has passed
• In times of minimal stress the parasympathetic nervous system also helps to maintain the internal body environments in a steady, balanced state of normal functioning